Lighting has been identified as the element which most determines the quality of an image. Working with available light and using internal flash and external light sources were discussed. In addition to the light present, the amount of light on the image sensor, or exposure, is determined by the opening/closing of the aperture and the length of time that the shutter is open. To better understand exposure, this article will discuss aperture, shutter speed, and the concept of "bracketing".
Aperture is essentially the opening that allows light in through the lens. You will see aperture indicated in "f-stops". The smaller f-stops represent larger apertures and therefore more light coming in through the lens. To state it more directly, the larger the aperture the brighter the light obtained.
It is also important to realize that aperture also influences some of the focusing within a shot, known as depth of field. Technically, a camera can only focus on one item within a shot with items becoming less in focus the further they are from that point. The depth of field is the range or distance of items that are in focus; thus, an image with a narrow depth of field generally has a smaller area in focus. A wide depth of field is used when wanting detail throughout the shot but a narrow depth of field is desirable when a single object or person is the focus of the image. When using a larger aperture, depth of field is minimized while reducing aperture maximizes it.
Shutter speed is generally understood as the length of time the shutter is open. Slower shutter speeds allow for more light and faster shutter speeds less light. Therefore, a night shot often utilizes a slower shutter speed in addition to a larger aperture to maximize the light coming into the lens. Whenever a slow shutter speed is utilized the risk of camera shake is significantly increased and thus, tripods are often necessary to avoid blurring.
Fast shutter speeds, such as 1/250, produce very sharp images and can act to freeze action. A slow shutter speed produces less defined images; images that demonstrate movement by blurring action. Just as with aperture size, the shutter speed selected is not "right" or "wrong", it is merely which will create the type of image wanted.
It is important to understand that when adjusting shutter speed or aperture size it is often necessary to adjust the other to accommodate the resulting change in lighting. For instance, if a faster shutter speed is chosen to freeze action aperture size may need to be increased to obtain adequate lighting for the shot while realizing that there will be a narrower depth of field.
Digital cameras offer the user control over aperture and shutter speed. For the novice, a Fully Automatic Mode in which the camera decides on the shutter speed, aperture, white balance, and focus is most handy. This feature is often sufficient for producing excellent photos but there are limitations. For instance, the camera will not sense when the user is attempting to take a shot which captures faster action. Use of a shutter speed that is too slow in this instance will result in blurring. As described above, it may be advisable to adjust the shutter speed, and possibly the aperture size, for this type of shot.
Many digital cameras also possess a Programmed Mode which allows the user to select the situation that is most appropriate; for instance portrait, sports, or landscape, and the camera makes the decisions from there. As discussed above, adjustments in the shutter speed to allow you to create special effects may be desired but not congruent with what the camera assumes is wanted.
Most digital cameras offer a Shutter Priority setting that allows the user to adjust the shutter speed while the camera determines the aperture and other features. In other instances, increased depth of field may be desired and achieved by selecting a smaller aperture. This is possible using the camera's Aperture Priority setting which will allow aperture alone to be adjusted. The Manual Mode allows both the shutter speed and aperture to be manually controlled. Obviously, this mode allows for the most control of shots but requires a significantly higher level of skill.
A final word about getting the best exposure with a digital camera is about a technique called "bracketing". Bracketing is used when it is difficult to determine the optimum exposure because the lighting varies within the scene. For instance, taking a photograph of a dog sitting in a snow covered field presents challenges based on the extreme contrast and reflection.
Bracketing is simply the practice of taking several shots of the same scene with different exposures. Most digital cameras make this very easy to do as they can automatically vary the exposure, taking a shot at the metered setting and others which are under exposed and over exposed. The user then compares the images, selects the best one, and deletes the rest. During the editing process it is even possible to combine the best parts of multiple shots to get the best composite image.
Although automatic settings produce great images, even a novice can adjust shutter speed and aperture to capture action and create special effects within their photographs. Digital cameras make the process easier and less expensive through progressively manual controls and the option of deleting photographs that simply aren't desirable.
Canon Eos Digital Photography
The amount of light on the image sensor, or exposure, is determined by the opening/closing of the aperture, the length of time that the shutter is open, and the amount of light present. For the purposes of this article, the discussion will be limited to working with and enhancing the light present for the shot.
When the light in a situation is not sufficient or when you want to create a different effect with highlights and shadows, an internal flash or external light source can be used. The happy news for the photography novice is that digital cameras have an auto flash feature in which the camera decides when lighting is insufficient and will activate the flash automatically.
One of the most important things to remember about using flash photography for the novice is that all cameras have a flash range. Beyond that range, generally no more than 14 to 15 feet, the flash is not effective. Flash is most often used when shooting indoors where there is generally less light. One of the pitfalls of using flash when photographing people and animals however is the infamous "red eye" effect which is created when the light bounces off of the back of the retina of the subject. This can be reduced by having subjects avoid looking directly into the camera or using the "red eye reduction" mode. This mode simply emits a tiny flash prior to taking the picture to help the pupil contract prior to the full flash.
Glare is another common problem encountered when using flash photography but can easily be eliminated by being sure not to point the camera directly into any shiny object such as a mirror or glass. Most digital cameras allow the user to have control of the flash function giving them the ability to disable it for use in situations where flash is not allowed or the user is striving to achieve a particular look in the picture. It also allows the user to set the flash so that it is always on, allowing the flash to be used even when the camera senses adequate lighting.
Flash can be used to deal with some lighting related problems outdoors as well. Sunlight can create shadows and cause the subject to appear dark and difficult to discern with the brighter, sunlit area around them. One option is to pose your subject in the shade. Taking photographs in the shade often provides images with better/truer color definition, no shadows, and subjects free from squinting.
When in the sunlight, use of the flash can be particularly helpful in balancing the light and reducing shadows. The fill-flash mode can be useful in any situation where the subject will be darker than the surrounding background whether they are shaded by a hat, a tree, or simply their own facial features. However, fill-flash mode should be used only when the subject is within 6 feet. Beyond this distance full power mode will be necessary.
Use of an external or auxiliary flash can give the user the control necessary to adjust lighting and create special effects. Just as the intensity of a light source influences the exposure in a picture, the direction of the light source can change an image through shadows and highlights. A flash can be attached to a camera with either a "cold shoe" or a "hot shoe". A cold shoe is merely a plastic shoe that allows the flash to be physically attached to the camera but does not have any contacts that allow the camera to communicate or coordinate the flash activity. With a hot shoe, users can attach a flash sync cord, allowing them to move the flash away from the camera and choose the direction of the lighting. In addition, a hot shoe attachment allows the flash to be controlled by the camera's flash settings. With the external flash, there are various modes to control the flash function.
?The TTL setting allows the camera and flash to determine the best exposure based upon the focal length of the lens. This is possible when the camera and the flash are of the same brand.
?The Stroboscopic setting can produce multiple flashes within a single exposure to create special effects.
?The Manual setting allows the user to set the flash for full, half, or quarter power.
?The Auto setting allows the flash to determine the best exposure independently. This is used most often when the camera and flash are not of the same brand.
There are two primary types of lighting used in photography. A hard light is created from a single, bright source of light and it produces shadows, highlights and pronounced contrast in the resulting image. Soft light on the other hand is very diffuse, making highlights and shadows more subtle.
Hard light is preferable when detail and distinct color is desired, but soft light is best for a softer image. Light from a single source can be diffused in a number of ways. The flash can be covered with a thin material such as tissue or wax paper or it can be bounced off of another surface, such as the ceiling or a wall, rather than being shown directly onto the subject. Bouncing the light is obviously not effective outdoors and the distance of the reflecting structure should be no more than 6-8 feet. The color of the surface reflecting the light must also be considered. Any color on the surface is generally reflected onto the subject. For this reason, white is generally preferred although professionals use black to absorb light and darken shadows and shiny materials are used to harden the light.
As mentioned previously, the direction of lighting can also greatly influence the characteristics of a photograph. The use of an external flash gives the user the option of moving the light source in relation to the subject. Front lighting is the most common. When wanting to emphasize the detail of the subject, front lighting is the best choice. However, it can create a rather harsh image with shadows in the background, muted colors in the foreground, and red eye. The use of fill flash and red eye reduction when using front lighting can help to alleviate some of the negative effects, while diffusing the light can reduce harshness.
Back lighting can produce a very dramatic photograph but, if too bright, can cause the subject to appear only as a silhouette unless the object is transparent. Reducing the brightness of the light source and using fill flash to brighten the shadowed areas can improve the quality of a picture with back lighting. Providing lighting from an angle rather than directly from the front or back can be beneficial in either of these lighting situations.
Lighting can also be directed from the side, the top, and from under the subject. Side lighting gives the user the most options as far as angle and the ability to create a wide variety of effects. Side lighting is optimal for creating texture and a sense of depth to a photograph.
For the novice photographer, experimentation is key. Whether diffusing light for softer images, using fill flash outdoors to eliminate shadows, or altering the direction of lighting to create special effects, creating unique, quality images requires practice.
Christine Peppler has sinced written about articles on various topics from Digital Camera, Entertainment Guide and Computers and The Internet. Christine Peppler is webmaster of homemedias.info, an online . Visit her site today for more basic photography tips or to learn more about selecting. Christine Peppler's top article generates over 246000 views. to your Favourites.
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